This invention relates to systems and mechanisms for handling flat articles such as mixed mail and, more particularly, to a mechanism which maintains the face orientation of such articles as they are dropped from a transport mechanism into a receptacle.
In systems for processing or otherwise handling mail, particularly mixed mail, or other flat articles, such articles are frequently diverted from an existing transport path and dropped into a suitable receptacle. An example of this is, for example, the sorting of mail by zip code, or the sorting of other articles such as flat parts, audio, video or computer discs, audio tapes and the like by part or item number. It is frequently desirable that the face orientation of the article remain unchanged after such drop to facilitate further processing of the articles at, for example, another location. For example, mail going to a given five-digit zip code might be sorted and bundled and then sent to a central post office at such zip code where it can be further sorted automatically by 11-digit zip code address or the like. Mail in such a package having the same orientation greatly facilitates such downstream processing.
However, since such articles are frequently discharged down an angled chute and can have a drop from the chute to the receiving receptacle of a foot or more, the aerodynamics of a flat article are such that both the face which is exposed at the bottom of the fall and the orientation of such face may undergo substantial change during the fall. While some mechanisms have heretofore been used to minimize this problem, these mechanisms have taken up considerable space in the vertical direction, thereby increasing the vertical footprint of each receptacle station and reducing the number of layers of such stations which can be accommodated in a given space by as much as 50%. Further, while these devices sometimes reduce the angle of the articles at the beginning of the drop, seeking to maintain the articles substantially horizontal at the beginning of the drop, they also can add close to a foot to the article drop distance, this added drop distance increasing the likelihood of a face orientation change for the article during the drop.
A need therefore exists for an enhanced mechanism for controlling the drop of flat articles from a transport and handling mechanism for such articles into an appropriate receptacle at various drop stations along an article handling transport system, which mechanism has as small a vertical footprint as possible so as to minimize any increase in vertical dimension caused by the presence of such device, while substantially assuring that the drop does not alter the face orientation of the article.
In accordance with the above, this invention provides a mechanism for receiving flat articles moving in a travel path with a substantially horizontal orientation and for dropping selected such articles into a receptacle position below the mechanism while maintaining the substantially horizontal article orientation for all such articles. The mechanism includes a holding station into which each article to be dropped is initially deposited, the holding station being just below the travel path; a retractable floor for the holding station; and a driver selectively operable for rapidly retracting the floor in a substantially horizontal direction to permit articles accumulated in the holding station to drop substantially vertically into the receptacle. The floor of the holding station may be a shutter slidable in a substantially horizontal plane between a first position under the holding station, and a second position out from under the holding station. Alternatively, the floor may be an iris mechanism having an extended position under the holding station and a retracted position out from under the holding station. The driver may, for example, be a pneumatic or hydraulic cylinder and may be operated, for example, in response to the holding station being filled by a selected amount, for example a selected thickness of articles or a selected number of articles in the holding station.
Where there are a plurality of receptacles positioned below the mechanism, a holding station of the type indicated above may be provided for each receptacle, which holding station is positioned just below the travel path and over the corresponding receptacle. A separate driver may be included for each of the holding stations or a common driver may be provided for at least a plurality of such holding stations. In the latter case, this driver may be operated in response to one of the holding stations reaching a selected fill level or possibly the passage of a selected time interval since the driver was last operated. Each of the holding stations for an embodiment with multiple holding stations is otherwise substantially the same as the single holding station described above.